Inductive voltage regulator



Oct. 19, 1965 E. STILPHEN INDUGTIVE VOLTAGE REGULATOR Filed Oct. 9, 1962 INVENTOR l l I 1 LEE 5. ST/LPHE ATTORNEY United States Patent 3,213,353 INDUCTIVE VOLTAGE REGULATOR Lee E. Stilpheu, 1036 Betts NE, Albuquerque, N. Mex. Filed Oct. 9, 1962, Ser. No. 229,395 11 Claims. (Cl. 32346) This invention relates to voltage regulators, and more particularly, has reference to an induction-type voltage regulator with relatively movable cores.

In induction-type voltage regulator devices the voltage output can be changed by varying the flux linkages of the alternating magnetic flux inducing voltage in the secondary coil. One way to change the linkages is to alter the relative position of the exciting (primary) and the excited (secondary) core. A change in the relative position of the two cores may include a variation of distance between the cores (that is, increasing or decreasing the air gap between them), a change in their relative angular position or both.

It is common practice to connect the primary exciting) winding across the line whose voltage is to be regulated. The secondary usually is connected in series with the line. The voltage induced in the secondary then either adds to or subtracts from the primary line voltage according to the relative positions of the primary and secondary coil windings.

This invention relates to an inductive voltage regulator having relatively angularly movable coaxial cores. Devices of this type known by those skilled in the art have windings wound in slots as in motors. Similarly to motors, there are provided an internal rotary core and a surrounding stationary core. Either core may carry either the primary or the secondary winding. When the axes of the primary and the secondary windings are in line, a maximum number of flux linkages will appear in the secondary core, causing a maximum induced voltage in the secondary coil winding. On the other hand, when the axes are at right angles, there will be no flux linkages in the secondary core. Consequently, no voltage will be induced in the secondary coil winding. Any intermediate value of the secondary induced voltage can be obtained by setting the angle between the axes at any value between zero and 90 degrees. Due to the fact that in devices known in the prior art the windings are disposed in slots similar to motor structures, the voltages used are limited. Furthermore, the regulator rotors of such devices are subjected to severe strain which causes bearing problems and noise. Also, it is an inherent disadvantage of such structures that the air gap between the two cores must be held at an undesirably large value.

Accordingly, this invention provides an improved inductive voltage regulator of simple construction for the purpose of obviating the foregoing shortcomings.

It is, therefore, an object of this invention to provide an improved induction type voltage regulator with relatively angularly movable cores wherein a much wider range of voltages may be used than in the previously known inductive voltage regulators.

It is a further object of this invention to provide an induction type voltage regulator with improved suspension means for its rotary core.

Another object of this invention is to provide an inductive voltage regulator of an improved structure wherein the rotary core is exposed to much less strain than in regulators having a motor-like structure.

A still further object of the invention is to provide an induction type voltage regulator of an improved structure wherein the air gap between the rotary and stationary cores may be extremely small.

It is a still further object of this invention to provide means for suppressing the noise in an induction type voltage regulator having relatively rotatable cores.

"ice

Objects and advantages other than those set forth above will be apparent from the following description of a preferred embodiment of the invention with reference to the accompanying drawing in which:

FIG. 1 is a schematic perspective drawing of one embodiment of the invention with the two cores in a neutral no regulation position;

FIG. 2 is a schematic perspective drawing of the same embodiment with the two cores in a maximum regulation position;

FIG. 3 is a plan view of the bottom of the upper core shown in FIGS. 1 and 2;

FIG. 4 is a vector diagram illustrating the effect of capacitance across the secondary coil; and

FIG. 5 is an elevation view of an embodiment of the voltage regulator with the coils removed.

The operation and basic structure of the variable voltage regulator of this invention will now be described with particular reference to FIGS. 1 and 2.

Referring to FIG. 1 there is provided a stationary magnetic core 1 having two parallel spaced upwardly extending legs 2 and 3. Positioned along the longitudinal axis of core 1 is rotary core 4 adapted to be rotated about its axis and having parallel spaced downwardly extending legs 5 and 6 facing the end faces 12 and 13 of legs 2 and 3, respectively. Legs 2 and 3 are separated from legs 5 and 6 by a narrow air gap 7 greatly magnified in FIGS. 1 and 2 for clarity. The resistance of gap 7 offered to the magnetic flux is negligible relative to the resistance of space 10 between legs 2 and 3.

An exciting or primary coil 8 is wound around legs 5 and 6 of rotatable core 4 and is connected across the leads of the AC. line voltage V. A secondary coil 9 is wound around legs 2 and 3 of core 1 and is in series with the load L.

As seen in FIG. 1, axially rotatable core 4 is set at right angles with respect to the stationary core 1. It is to be noted in particular that in this relative position of the two cores, faces 12 and 13 bridge squarely space 11. Thus, core 1 constitutes a magnetic shunt for exciting core 4. As a result of this relative position of the two cores, the flux generated by coil 8 in core 4 will, from one leg of core 4, enter both legs 2 and 3 simultaneously, then extend within legs 2 and 3 parallel to and in the proximity of faces 12 and 13, and will eventually return into the other leg of core 4 without intersecting any loop of secondary coil 9. Consequently, no voltage is induced in coil 9 by primary coil 8. The broken lines in FIG. 1 represent the course of the flux outside exciting core 4. The degree relative position of the two cores will be hereinafter referred to as neutral or no regulation position.

Referring now to FIG. 2, it is seen that core 4 has been rotated 90 degrees and it now assumes a zero degree position with respect to core 1. Legs 2 and 3 no longer bridge space 11 between legs 5 and 6 of core 4. As a result of this relative position of the two cores, the magnetic flux generated by coil 8 in core 4 will flow from one leg of core 4 across air gap 7 into one leg of core 1, then follow the magnetic path of the entire core 1 and finally flow back from the other leg of core 1 into the other leg of core 4 through air gap 7. Thus, the entire flux generated in core 4 will intersect the loops of secondary coil 9 and maximum voltage will be induced therein. The course of the flux is represented by broken lines in FIG. 2. The zero degree relative position of the two cores will be hereinafter referred to as maximum regulation or full regulation position.

It will be readily understood that by setting the rotatable core to any desired angle with respect to the stationary core a wide range of regulation can be obtained between no regulation and full regulation. As core 4 is rotated in either direction from the neutral position, soon a relative position between the two cores will be reached where the secondary core 1 no longer acts as a magnetic shunt for core 4. Moving the core 4 further beyond this point, at first very weak regulation will be experienced. This regulation increases gradually as the end faces of legs 2, 3 and 5, 6, respectively, approach more and more a face-to-face position. Eventually, full regulation is obtained when the aforesaid face-to-face position is reached.

The amount of full regulation, as it is known to those skilled in the art, depends on the ratio of the number of turns in the two coil windings. For example, to arrive at a 20% maximum regulation, the ratio of turns of coil 8 to the turns of coil 9 should be five to one.

The voltage induced may either boost or buck the line voltage. Whether the voltage induced across the primary coil adds (boosts) to or subtracts (bucks) from the line voltage depends solely on the momentary direction of the load current fiow in the secondary coil with respect to the direction of the momentary flux in the secondary core. It is obvious that the direction of the flux in the secondary core is changeable with respect to the load current and depends on the direction in which the rotatable core is turned from the neutral position.

As set forth precedingly, in neutral position it is desired that no induced voltage appear across the secondary coil 9. In view of the fact, however, that alternating load current is flowing in coil 9, a self-induced bucking voltage will appear thereacross. Since coil 9 is made of heavy wire and has few turns, the voltage drop it causes due to its ohmic resistance will be small. Consequently, the self-induced flux in core 1 will be weak and can be easily compensated. To this end core 4 is surrounded, as close to core 1 as possible, by a short-circuited winding of a single turn preferably in the form of a copper strap 14. As shown in FIG. 3, strap 14 is divided into two loops A and B by copper band 15 received by transversal slots 16 and 17 in legs and 6, respectively. In neutral position end faces 12 and 13 of core 1 will register with loops A and B. Copper band 15 will extend along space between legs 2 and 3. The flux generated in core 1 by the load current in coil 9 will enter core 4 by cutting across one loop from one direction and will leave core 4 and return into core 1 by intersecting the other loop from the other direction. As a result current will flow in strap 14 and band generating a counter-flux in core 1. This counter-flux will greatly reduce the flux induced in core 1 by the load current carried by coil 9. On the other hand, in maximum regulation position end faces 12 and 13 of core 1 will be positioned squarely with respect to loops A and B. As a result, in maximum regulation position the flux generated by coil 9 in core 1 will not induce any current in the strap 14 since at any given moment the amount of flux generated in core 1 crossing each loop from one direction also intersects the same from the opposite direction, thus reducing the net flux to zero. The strong exciting flux generated by coil 8 in core 4 will, for similar reasons, at no time induce any current in either loop A or B.

In order to obtain an increased efiiciency in the voltage regulation, means are provided to compensate for the reactive lag of the induced voltage in coil 9. As seen in FIGS. 1 and 2, a condenser 18 is connected across coil 9. Referring now to the vector diagram shown in FIG. 4, the reactive voltage generated in coil 9 and represented by vector D-G is added to line voltage C-D with a lag of 0. When no capacitor is used C-G is the resultant reactive voltage. With the condensor in circuit, reactive voltage DE having a lead of 5, is also added to the line voltage. The resulting voltage is represented by vector C-F which is greater than the resulting voltage C-G, obtained without the capacitive reactance in the circuit.

It will be readily understood that in the induction regulator described hereinabove, certain changes may be brought about within the scope of the invention. For example, the heavy series winding which carries the load current can be wound around the rotary core in which case the primary winding would be positioned on the stationary core. In such an arrangement the exciting flux would be generated in the stationary core. Also, in order to compensate for the self-induced voltage in the series winding, the short-circuited copper strap would be mounted on the stationary core.

In FIG. 5, there are shown preferred mounting and operating means of the rotatable core. A rectangular frame comprising longitudinal beams 19, 20, stator core support beam 21 and rotor core support beam 22 is adapted to be mounted by any desired fastening means inside a protective housing (not shown). Stationary core 23 is fixedly secured to beam 21 by any desired known mounting means (not shown). Rotatable core 24 is suspended from beam 22 by means of shaft 25 secured to beam 22 by main bearing means comprising a top bearing 37 and a bottom bearing 36. At the bottom portion of core 24 there is provided a guide bearing assembly to prevent any swinging motion of core 24 away from its axis of rotation. The guide bearing assembly comprises a nonmetallic circular yoke 34 having a central aperture (not shown) to receive the bottom portion of both legs of core 24. Any desired fastening means such as screws 35 may be used to fixedly mount yoke 34 on core 24. Concentrically surrounding yoke 34 is guide ring 32 made of a bearing material. The guide ring 32 is attached to a bearing support beam 31 by means of bolts 33. Beam 31 extends parallel to stator core support beam 21 and is bolted or otherwise fastened to longitudinal beams 19 and 20. Any swinging motion that may be imparted upon core 24 will be checked by the cooperation of the external surface of yoke 34 and the internal surface of ring 32. For clarity the clearance between yoke 34 and guide 32 has been greatly magnified in FIG. 5. Core 24 is separated from core 23 by narrow air gap 30. Keyed to shaft 25 is a gear wheel 26. Meshing gear 26 is drive gear 27 keyed to the shaft of electric motor 28. Suitable controls (not shown) are provided for actuating the motor 28, and thereby adjusting core 24 to the desired angular position with respect to core 23. A compression spring 29 is disposed around shaft 25 between beam 22 and core 24 exerting a constant pressure to the latter and urging it toward core 23. The principal function of spring 29 is to prevent core 24 from vibration during operation, commonly known in the art as chattering.

Although but one embodiment of the invention has been depicted and described, it will be apparent that this embodiment is illustrative in nature and that a number of modifications in the apparatus and variations in its end use may be effected without departing from the spirit or scope of the invention as defined in the appended claims.

I claim:

1. An inductive voltage regulator comprising a stationary magnetic core having a first coil wound thereon, means for fixedly supporting said stationary core, a movable magnetic core having a second coil wound thereon, said movable core spaced from said stationary core along the prolonged longitudinal axis thereof and separated by a narrow air gap therefrom, main bearing means disposed on su porting means for suspending said movable core therefrom and maintaining said movable core out of physical contact with said stationary core, guide bearing means surrounding the end portion of said movable core distal from said main bearing means and means for moving said movable core with respect to said stationary core.

2. An inductive voltage regulator comprising a stationary magnetic core having a first coil wound thereon, means for fixedly supporting said stationary core, a movable magnetic core having a second coil wound thereon, said movable core spaced from said stationary core along the prolonged longitudinal axis thereof and separated by a narrow air gap therefrom, main bearing means disposed on supporting means for suspending said movable core therefrom and maintaining said movable core out of physical contact with said stationary core, guide bearing means surrounding the end portion of said movable core distal from said main bearing means, spring means disposed at the end portion of said movable core adjacent said main bearing means for urging said movable core towards said stationary core in the direction of the longitudinal axis thereof and means for moving said movable core with respect to said stationary core.

3. An inductive voltage regulator comprising a stationary magnetic core having a first coil wound thereon, means for fixedly supporting said stationary core, a rotatable magnetic core having a second coil wound thereon, said rotatable core Spaced from said stationary core along the prolonged longitudinal axis thereof and rotatable thereabout, said cores being separated by a narrow air gap, main bearing means disposed on supporting means for suspending said rotatable core therefrom and maintaining said rotatable core out of physical contact with said stationary core, guide bearing means surrounding the end portion of said rotary core distal from said main bearing means for preventing motion of said rotary core laterally from the longitudinal axis thereof and means for rotating said rotatable core to any desired position with respect to said stationary core.

4. An inductive voltage regulator comprising a stationary magnetic core having a first coil wound thereon, means for fixedly supporting said stationary core, a rotatable magnetic core having a second coil wound thereon, said rotatable core spaced from said stationary core along the prolonged longitudinal axis thereof and rotatable thereabout, said cores being separated by a narrow air gap, main bearing means disposed on supporting means for suspending said rotatable core therefrom and maintaining said rotatable core out of physical contact with said stationary core, guide bearing means surrounding the end portion of said rotary core distal from said main bearing means for preventing motion of said rotary core laterally from the longitudinal axis thereof, spring means disposed between said main bearing means and the end portion of said rotary core adjacent said main bearing means for urging said rotary core toward said stationary core and means for rotating said rotatable core to any desired position with respect to said stationary core.

5. An inductive voltage regulator comprising a stationary U-shaped magnetic core having end faces and carrying a first coil wound thereon, a support frame adapted for receiving said stationary core, a rotatable magnetic core of substantially the same geometrical configuration as said stationary core, said rotatable core carrying a second coil wound thereon and having an axis of rotation coinciding with the prolonged longitudinal axis of said stationary core, the end faces of said cores facing each other and separated by a narrow air gap from one another, main bearing means disposed on said support frame for suspending said rota-table core therefrom and maintaining said rotatable core out of physical contact with said stationary core, guide bearing means surrounding the end portion of said rotary core distal from said main bearing means, said guide bearing means including a yoke fixedly mounted on said rotary core and a stationary ring member concentrically surrounding said yoke and fixedly mounted on a stationary support attached to said support frame, a coil spring disposed between said support frame and the end portion of said rotatable core adjacent said main bearing means for urging said rotary core toward said stationary core and means for rotating said rotatable core to any desired angular position with respect to said stationary core.

6. An inductive voltage regulator comprising a stationary magnetic core having a first coil wound thereon, means for fixedly supporting said stationary core, a movable magnetic core having a second coil wound thereon, one of said coils connected to the line voltage to be regulated, the other of said coils connected in series with a load supplied with current from said line voltage, a capacitor connected across said series coil for bringing the reactive voltage generated therein in phase with said line voltage, said movable core spaced from said stationary core along the prolonged longitudinal axis thereof and separated by a narrow air gap therefrom, main bearing means disposed on supporting means for suspending said movable core therefrom and maintaining said movable core out of physical contact with said stationary core, guide bearing means surrounding the end portion of said movable core distal from said main bearing means and mean-s for moving said movable core with respect to said stationary core.

7. An inductive voltage regulator comprising a stationary magnetic core having a first coil wound thereon, means for fixedly supporting said stationary core, a movable magnetic core having a second coil wound thereon, one of said coils connected to the line voltage to be regulated, the other of said coils connected in series with a load supplied with current from said line voltage, a capacitor connected across said series coil for bringing the reactive voltage generated therein in phase with said line voltage, said movable core spaced from said stationary core along the prolonged longitudinal axis thereof and separated by a narrow air gap therefrom, main bearing means disposed on supporting means for suspending said movable core therefrom and maintaining said movable core out of physical contact with said stationary core, guide bearing means surrounding the end portion of said movable core distal from said main bearing means, spring means disposed at the end portion of said movable core adjacent said main bearing means for urging said movable core towards said stationary core in the direction of the longitudinal axis thereof and means for moving said movable core with respect to said stationary core.

8. An inductive voltage regulator comprising a stationary magnetic core having a first coil wound thereon, means for fixedly supporting said stationary core, a rotatable magnetic core having a second coil wound thereon, one of said coils connected to the line voltage to be regulated, the other of said coils connected in series with a load supplied with current from said line voltage, a capacitor connected across said series coil for bringing the reactive voltage generated therein in phase with said line voltage, said rotatable core spaced from said stationary core along the prolonged longitudinal axis thereof and rotatable thereabout, said cores being separated by a narrow air gap, main bearing means disposed on supporting means for suspending said rotatable core therefrom and maintaining said rotatable core out of physical contact with said stationary core, guide bearing means surrounding the end portion of said rotary core distal from said main bearing means for preventing motion of said rotary core laterally from the longitudinal axis thereof and means for rotating said rotatable core to any desired position with respect to said stationary core.

9. An inductive voltage regulator comprising a stationary magnetic core having a first coil wound thereon, means for fixedly supporting said stationary core, a rotatable magnetic core having a second coil wound thereon, one of said coils connected to the line voltage to be regulated, the other of said coils connected in series with a load supplied with current from said line voltage, a capacitor connected across said series coil for bringing the reactive voltage generated therein in phase with said line voltage, said rotatable core spaced from said stationary core along the prolonged longitudinal axis thereof and rotatable thereabout, said cores being separated by a narrow air gap, main bearing means disposed on supporting means for suspending said rotatable core therefrom and maintaining said rotatable core out of physical contact with said stationary core, guide bearing means surrounding the end portion of said rotary core distal from said main bearing means for preventing motion of said rotary core laterally from the longitudinal axis thereof, spring means disposed between said main bearing means and the end portion of said rotary core adjacent said main bearing means for urging said rotary core toward said stationary core and means for rotating said rotatable core to any desired position with respect to said stationary core.

10. An inductive voltage regulator comprising a stationary U-shaped magnetic core having end faces and carrying a first coil wound thereon, a support frame adapted for receiving said stationary core, a rotatable magnetic core of substantially the same geometrical configuration as said stationary core, said rotatable core carrying a second coil wound thereon, one of said coils connected to the line voltage to be regulated, the other of said coils connected in series with a load supplied with current from said line voltage, a capacitor connected across said series coil for bringing the reactive voltage generated therein in phase with said line voltage, said rotatable core having an axis of rotation coinciding with the prolonged longitudinal axis of said stationary core, the end faces of said cores facing each other and separated by a narrow air gap from one another, main hearing means disposed on said support frame for suspending said rotatable core therefrom and maintaining said rotatable core out of physical contact with said stationary core, guide bearing means surrounding the end portion of said rotary core distal from said main bearing means, said guide bearing means including a yoke fixedly mount- (.1 ed on said rotary core and a stationary ring member concentrically surrounding said yoke and fixedly mounted on a stationary support attached to said support frame, a coil spring disposed between said support frame and the end portion of said rotatable core adjacent said main bearing means for urging said rotary core toward said stationary core and means for rotating said rotatable core to any desired angular position with respect to said stationary core.

11. An inductive voltage regulator comprising a stationary magnetic core having a first coil wound thereon, means for fixedly supporting said stationary core, a movable magnetic core having a second coil wound thereon, said movable core spaced from said stationary core along the prolonged longitudinal axis thereof and separated by a narrow air gap therefrom, main bearing means disposed on supporting means for suspending said movable core therefrom and maintaining said movable core out of physical contact with said stationary core, guide bearing means surrounding said movable core and means for moving said movable core with respect to said stationary core.

References Cited by the Examiner UNITED STATES PATENTS 3,035,439 3/36 Crossley 32352 X 2,585,050 2/52 Simon 323-46 2,609,531 9/52 Kirchner 336-119 X 2,948,842 8/60 Ditto 323-5l LLOYD MCCOLLUM, Primary Examiner. 

11. AN INDUCTIVE VOLTAGE COMPRISING A STATIONARY MAGNETIC CORE HAVING A FIRST COIL WOUND THEREON, MEANS FOR FIXEDLY SUPPORTING SAID STATIONARY CORE, A MOVABLE MAGNETIC CORE HAVING A SECOND COIL WOUND THEREON, SAID MOVABLE CORE SPACED FROM SAID STATIONARY CORE ALONG THE PROLONGED LONGITUDINAL AXIS THEREOF AND SEPARATED BY A NARROW AIR GAP THEREFROM, MAIN BEARING MEANS DISPOSED ON SUPPORTING MEANS FOR SUSPENDING SAID MOVABLE CORE THEREFROM AND MAINTAINING SAID MOVABLE CORE OUT OF PHYSICAL CONTACT WITH SAID STATIONARY CORE, GUIDE BEARING MEANS SURROUNDING SAID MOVABLE CORE AND MEANS FOR MOVING SAID MOVABLE CORE WITH RESPECT TO SAID STATIONARY CORE. 